1. Field of Invention
The invention relates to methods and devices for the transfer of signatures. In particular the invention relates to a device for the transfer of signatures in which a first and a second gathering chain have a joint transfer region for transferring the signatures. Respective conveying chains of the first and second gathering chains are arranged offset to the side and parallel to each other, at least in this transfer region. The first gathering chain is provided with a ridge as well as a number of pushers for moving the signatures that are positioned straddling on the ridge in a conveying direction and for transferring these signatures in the transfer region to the second gathering chain. The second gathering chain comprises at least one conveying chain with pushers arranged at a pre-defined distance to each other. The invention also relates to a method that can be realized with the aid of a device for the transfer of signatures. Further, the invention relates to a gathering and wire-stitching machine that includes a device for the transfer of signatures.
2. Related Art
During further processing, the signatures are conveyed, among other things, with the aid of so-called gathering chains which are typically used in gathering and wire-stitching machines. Gathering and wire-stitching machines are machines in which completely printed, folded signatures that are stored temporarily in feeders are gathered, are aligned and are subsequently provided with wire-stitching along the spine, for example, in a stitching machine. As a rule, the signatures are initially conveyed by a first, single gathering chain in the direction of the stitching machine. Even before reaching the stitching machine, the signatures are transferred from the first gathering chain to a second, dual gathering chain which then supplies the signatures to the stitching machine. The second gathering chain may also be embodied as a single gathering chain. An essential aspect of this type of further print material processing is that the signatures should be processed and/or transferred from one station to the next as carefully as possible. A number of devices and methods have already been developed to ensure that the signatures are transferred from a first to a second gathering chain in the most careful manner possible.
European patent document EP 0881180 A1 discloses a conveying system for gathering and processing signatures. The conveying system comprises a first, single and a second, dual gathering chain, as well as a transfer region where the single gathering chain enters the dual gathering chain. Pushers which are responsible for moving along the signatures are arranged on the single gathering chain. Each signature sits straddling on a ridge of the single gathering chain. To prevent an uncontrolled conveying of the signatures with non-defined spacing, relative to each other, a pusher is arranged behind each signature to ensure that it is conveyed in transporting direction. The pushers are mounted upright on the single gathering chain and are submerged in the transfer region while the dual gathering chain takes over the respective signature. As a result of the upright positioning, the pushers on the single gathering chain tilt in conveying direction while being submerged, thereby providing an additional push to the signatures. This can have the effect of leaving a mark in the back region of its signature fold.
European patent document EP 1424211 A1 discloses a device for producing bound printed products. The gathering chain comprises pushers arranged on the side. At the end of the gathering chain, the signatures are transported via a support plate to an intermediate conveying region from which they are supplied with the aid of an intermediate conveyor and via a sword to a stitching line. The stitching line in this case corresponds to the above-mentioned dual gathering chain. This solution has the disadvantage of using additional elements in the intermediate conveying region, for example the support plate, which results in making the system more expensive.